The officials didn't provide a specific number for those detained, but did say they were arrested on order's from Saleh's son Ahmad for either allegedly holding secret talks or leaking information to Saleh's opponents.

Officials say most of those arrested were from the highly trained Republican Guards, commanded by Ahmad Saleh.

The arrests in the ranks of the Republican Guard come as Yemen's military finds itself losing its grip on the southern regions of the country.

Under Seige

The commander of the 25th brigade in southern Yemen on Monday appealed relief saying his troops were trapped on base.

From his base a few kilometers outside Zinjibar, Khalid Noamani said his brigade had sent an urgent plea for help.

"We call on the country to send support to the troops of the 25th brigade; we have been blockaded for over a month and have not received human reinforcements, equipment, or even a drop of water in over two weeks," Noamani told Reuters by telephone. "There are battles here day and night."

Noamani said terrorists positioned atop buildings near the base had blockaded his brigade of several hundred troops.

Political Paralysis

Mass protests demanding an end to President Ali Abdullah Saleh's three-decade rule have paralyzed Yemen. The southern Abyan province has descended into violence with militants suspected of ties to Al Qaida challenging the military for control.

In recent months, militants have seized control of two cities in Abyan, including the provincial capital Zinjibar. Last week they gained control of a stadium outside Zinjibar, which the army had been using for refuelling and supplies.

Yemen's Defence Ministry said on Saturday it will step up military operations and will deploy a security belt around the southern port city of Aden, entryway to the country's strategic Red Sea shipping lane.

The United States and neighboring Saudi Arabia have been targets of foiled attacks by Al Qaida's Yemen-based wing and worry the power vacuum from a six-month struggle between protesters and the government may give the group more room to operate.

Opposition Not Buying It

Opposition groups accuse the government of intentionally letting the violence escalate in order to frighten the international community that Yemen would collapse into chaos without Saleh at the helm.

Saleh is recovering in Riyadh from wounds sustained in an assassination attempt last month, but has signaled he will cling to power despite analysts' expectations he will be unable to retake the reins.